What is Compost? Video Lecture | Basic Science for Primary 5

Do you remember when we were talking about
recycling…
...and how we can turn things like old paper,
metal or plastic into new things?
Well: Did you know that you can also recycle
plants?
It’s true!
And you do it, by turning stuff like dead
leaves, apple cores, and kitchen scraps into
… compost!
Compost is a special kind of dirt that you
can make, by setting aside certain kinds of
trash … and letting it rot.
It might seem kind of yucky to keep a bunch
of old banana peels and dead leaves around.
But this waste will eventually turn to compost,
which you can use in your garden to grow flowers
or vegetables or anything you want!
So, how do we get from trash…to yummy veggies?
Have you ever been out for a walk, and seen
an apple core that someone dropped on the
ground?
After a while it gets all brown, mushy, and
kind of slimy.
And eventually…it seems to sort of disappear.
But it doesn’t just go away.
It decomposes.
When something decomposes, it breaks down
into teeny tiny pieces.
And decomposing is helped along by a group
of living things called decomposers.
Now that’s a pretty great name because decomposers
get their energy by breaking down things that
were once alive.
That apple core?
It was part of an apple tree.
And the bread crust from your sandwich?
That was made from ground-up parts of the
wheat plant.
Decomposers use these bits of once-living
things as their own food...
...They basically eat our garbage!
Decomposers include things like mushrooms
that grow on rotting logs…and insects and
worms that eat the scraps that come from that
sandwich you didn’t finish.
They /even/ include tiny living things too
small for us to see.
These guys might sound like they have a pretty
gross job, but it’s a /really/ important
one!
Because decomposers turn those leftover parts
of living things into compost!
And compost is important, because it’s /full/
of nutrients!
/Your/ body uses nutrients from the food you
eat to build a healthy body.
And plants need nutrients, too!
They use nutrients to grow taller, and maybe
sprout some flowers, and make all of the plant-parts
that we eat as fruits and vegetables.
So, without decomposers, plants wouldn’t
be able to get the nutrients that they need.
Now, let’s see if we can put decomposers
to work, to make some compost!
Many people who make compost have a big bin
in their yard somewhere.
But if you don’t have a yard, you can /still/
make compost in a small container, like a
special compost bucket, or even an empty soda
bottle!
No matter what you use, to get good compost,
you need to follow a kind of a recipe, just
like cooks do in the kitchen!
Let’s start by looking at our bin.
The bin can be made of metal, wood, or plastic…but
it should have holes in it so that air can
get in and out.
Air is an important ingredient in making good
compost.
Because many decomposers, like insects and
worms, need air to breathe, just like you
do!
Next, we need our waste -- and we should group
it into two main colors.
That’s right, colors!
The waste you use to compost is generally
either green or brown.
Green waste includes things like kitchen scraps.
But we can’t use /all/ of the stuff that
we throw out in the kitchen.
Meat and cheese, for example, can attract
animals that might dig through our compost.
So stick to fruit and veggie scraps -- which
is mostly the green stuff.
Brown waste is usually...you guessed it....
brown!
This kind of waste includes dead leaves, straw,
and sawdust.
We need about two times as much brown waste
as green waste.
Put the green and brown waste into your bin
in layers ...
...and add water.
Now all we need are … our decomposers!
If your bin is outside, you can just wait.
Decomposers like insects and worms will move
right in and start munching on your waste.
If you’re composting inside, you can add
some earthworms to your compost bin, or even
find special red worms that are /really/ good
at making compost.
Oh, and I almost forgot!
We need patience.
Because composting takes time.
Depending on how big your bin is, it can take
months for decomposers to do their jobs and
to break down all of the waste.
If you want to help them out, give your compost
pile a little stir, or turn it over with a
shovel.
But while you’re waiting, do some observing!
If you watch your compost pile over time,
you’ll see some pretty cool things.
You might see some mushrooms start to grow
on it...and you should see a whole /lot/ of
different insects and worms.
If they’re doing their job well, and if
you’ve done a good job adding your ingredients...the
compost won’t even smell bad!
Once the wait is over, and your compost is
ready…it will look like…dirt!
But compost is more than plain old dirt.
Because, it’s packed full of nutrients that
the waste still had inside it!
So in a way, compost is a way you can recycle
plants into new plants!
It lets you turn garbage … into greenery!
Thanks for joining me on SciShow Kids!
And special thanks to our friend Elliott from
Portland, Oregon who asked us to make this
video!
Do /you/ have a question for us?
Let us know in the comments below, or email
us at Kids@TheSciShow.com!